[PATCH] tracing: hide unused functions

[PATCH] tracing: hide unused functions

[Arnd Bergmann]

After trace_selftest_startup_sched_switch is removed, trace_test_buffer()
is now only used inside of CONFIG_FUNCTION_TRACER, leading to this
warning:

kernel/trace/trace_selftest.c:62:12: error: 'trace_test_buffer' defined but not used [-Werror=unused-function]

The same is true for a few other functions called by trace_test_buffer(),
so let's extend the #ifdef to cover all of them together.

Fixes: d8c4deee6dc6 ("tracing: Remove obsolete sched_switch tracer selftest")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 kernel/trace/trace_selftest.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 364f78abdf47..bcdffeca9bd8 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -6,6 +6,8 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 
+#ifdef CONFIG_FUNCTION_TRACER
+
 static inline int trace_valid_entry(struct trace_entry *entry)
 {
 	switch (entry->type) {
@@ -98,7 +100,6 @@ static inline void warn_failed_init_tracer(struct tracer *trace, int init_ret)
 	printk(KERN_WARNING "Failed to init %s tracer, init returned %d\n",
 		trace->name, init_ret);
 }
-#ifdef CONFIG_FUNCTION_TRACER
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 
-- 
2.9.0

Re: [PATCH] tracing: hide unused functions

[Arnd Bergmann]

On Fri, Oct 13, 2017 at 2:01 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> After trace_selftest_startup_sched_switch is removed, trace_test_buffer()
> is now only used inside of CONFIG_FUNCTION_TRACER, leading to this
> warning:
>
> kernel/trace/trace_selftest.c:62:12: error: 'trace_test_buffer' defined but not used [-Werror=unused-function]
>
> The same is true for a few other functions called by trace_test_buffer(),
> so let's extend the #ifdef to cover all of them together.
>
> Fixes: d8c4deee6dc6 ("tracing: Remove obsolete sched_switch tracer selftest")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Nevermind, I ran into another problem with this applied: trace_test_buffer()
is used elsewhere after all, just not for all possible combinations.

Maybe marking it as __maybe_unused would be more appropriate?

      Arnd

Re: [PATCH] tracing: hide unused functions

[Steven Rostedt]

On Fri, 13 Oct 2017 15:02:34 +0200
Arnd Bergmann <arnd@arndb.de> wrote:

> On Fri, Oct 13, 2017 at 2:01 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> > After trace_selftest_startup_sched_switch is removed, trace_test_buffer()
> > is now only used inside of CONFIG_FUNCTION_TRACER, leading to this
> > warning:
> >
> > kernel/trace/trace_selftest.c:62:12: error: 'trace_test_buffer' defined but not used [-Werror=unused-function]
> >
> > The same is true for a few other functions called by trace_test_buffer(),
> > so let's extend the #ifdef to cover all of them together.
> >
> > Fixes: d8c4deee6dc6 ("tracing: Remove obsolete sched_switch tracer selftest")
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>  
> 
> Nevermind, I ran into another problem with this applied: trace_test_buffer()
> is used elsewhere after all, just not for all possible combinations.
> 
> Maybe marking it as __maybe_unused would be more appropriate?

If that quiets the warning for you. This selftest code isn't something
for production, so it shouldn't be that critical. It's only used to
sanity check various parts of tracing.

-- Steve